There is a school of thought which holds that only people who have led interesting lives and done great deeds should write their autobiographies. How dare a "glamour model" who goes by the name of Jordan and whose principal claim to fame is her surgically enhanced chest presume to write not one, but two accounts of her life? Amanda Platell made a powerful case against her recently in these pages. But I am not so sure. The lady has a tale to tell, her books sell by the cartload, and it is at least arguable whether the life of a lady with super-sized breasts is more or less interesting than the life of your average statesman.
Real heavyweights seldom produce the most interesting books - certainly not, in politics. Roy Jenkins was the exception but Willie Whitelaw was probably the rule. He might have had lots to say, but you would never guess it from his book. The Sunday Times paid megabucks to buy the serial rights, and then had to employ Brian Walden to interview him. Walden got Whitelaw to admit that he'd never socialise with Maggie - and that gave the paper a story. If it had relied solely on the memoirs, there would have been some rather large gaps in the paper's pages.
Many of our finest politicians have written autobiographies of such mind-numbing tedium that they should be packaged like those glossy comics aimed at teenage girls - with a small gift, ideally a razor blade and instructions for wrist-slitting after page 16. Outside politics, some of the most gripping autobiographies of recent years have been written by people few of us had ever heard of. Remember Frank McCourt and his Pulitzer Prize for Angela's Ashes?
Now we have John Simpson's autobiography. Actually that is not true. This is his fifth book about his life. Simpson is to memoirs what Ford was to automobiles: he has created an industry single-handed. And anyone who enjoys a good read should be grateful for that. Simpson is that uncommon beast: a man with something to say who says it with passion, humour and great style.
A good autobiography should do more than tell the story of the writer's life. Any competent hack journalist can do that, with the help of a reasonably sound memory and/or a vivid imagination. A good one has to be honest - painfully honest, on occasions. Once the reader starts to feel that the writer is stepping back, gauging the effect on his reputation of the last sentence with his finger poised over the "delete" key, the game is up. You never get that sense with Simpson. He is honest to the point where you almost wish he had eased off. His description of the way his parents' marriage fell apart is painful, and beautifully observed.
This is not a book about the public Simpson, the great reporter who has scarcely been off our television screens for 30 years, donning a burqa or liberating Kabul or getting blown up in Iraq. All that is in the other books. That stuff's easy to write - though, again, few people could have written it as well as him.
In Days From a Different World, Simpson returns to his childhood, already touched on in previous memoirs, because "the further I get through life the more I want to revisit it". He actually begins in the womb. Knowing John as I do, I suspect he was making notes in one of his hardback A4 notebooks on his way through the birth canal.
Simpson discloses for the first time that his father, Roy - a charmer and a cad who had a brief fling with Zsa Zsa Gabor - was bisexual. Endlessly in debt, he was "thrown out of the middle class with the door slammed in his face and the badges of rank ripped from his uniform". Cads make good copy. Simpson's writing about Roy reminded me of John le Carre writing about his father. That's meant as a compliment.
At one stage in his life, his father earned a living (just) by demonstrating Prestige Commodore pressure cookers at the Ideal Home Exhibition in Earls Court. Five-year-old "Johnny" was his unwilling assistant. After his father had proved beyond doubt that the Prestige could indeed cook vegetables very quickly, Simpson would be called on stage to drink the "residue", the faintly disgusting liquid left in the cooker when the vegetables had been removed. He hated it, but I wonder whether it gave him a taste for public performance.
Some say Simpson is too big for his boots on television and wants too much to be the centre of attention. That might be fair if attention-seeking got in the way of his telling the story, but it doesn't. On the contrary, if you are prepared to take the risks he takes and expose yourself as he does you are bound to become the centre of attention. He is a big man in every sense, and this book is another triumph.
John Humphrys's most recent book is Lost for Words: the mangling and manipulation of the English language (Hodder & Stoughton)